NATIONAL BUREAU OF STANDARDS REPORT

9909

IMPACT PROPERTIES OF ALUMINUM ALLOY - BETA

SILICON CARBIDE WHISKER COMPOSITES

To

Melpar, Inc.

(USAF Contract No. F 336 1 5-68 - C- 106 4)

U.S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

NATIONAL BUREAU OF STANDARDS

The National Bureau of Standards’ was established by an act of Congress March 3,1901. Today, in addition to serving as the Nation’s central measurement laboratory,the Bureau is a principal focal point in the Federal Government for assuring maxi-mum application of the physical and engineering sciences to the advancement of tech-nology in industry and commerce. To this end the Bureau conducts research andprovides central national services in three broad program areas and provides cen-tral national services in a fourth. These are: (1) basic measurements and standards,

(2) materials measurements and standards, (3) technological measurements andstandards, and (4) transfer of technology.

The Bureau comprises the Institute for Basic Standards, the Institute for MaterialsResearch, the Institute for Applied Technology, and the Center for Radiation Research.

THE INSTITUTE FOR BASIC STANDARDS provides the central basis within theUnited States of a complete and consistent system of physical measurement, coor-dinates that system with the measurement systems of other nations, and furnishesessential services leading to accurate and uniform physical measurements throughoutthe Nation’s scientific community, industry, and commerce. The Institute consistsof an Office of Standard Reference Data and a group of divisions organized by thefollowing areas of science and engineering

:

Applied Mathematics—Electricity—Metrology—Mechanics—Heat—Atomic Phys-ics—Cryogenics2—Radio Physics 2—Radio Engineering2—-Astrophysics 2—Timeand Frequency. 2

THE INSTITUTE FOR MATERIALS RESEARCH conducts materials research lead-ing to methods, standards of measurement, and data needed by industry, commerce,educational institutions, and government. The Institute also provides advisory andresearch services to other government agencies. The Institute consists of an Office ofStandard Reference Materials and a group of divisions organized by the followingareas of materials research:

Analytical Chemistry—Polymers—Metallurgy— Inorganic Materials— PhysicalChemistry.

THE INSTITUTE FOR APPLIED TECHNOLOGY provides for the creation of appro-priate opportunities for the use and application of technology within the Federal Gov-ernment and within the civilian sector of American industry. The primary functionsof the Institute may be broadly classified as programs relating to technological meas-urements and standards and techniques for the transfer of technology. The Instituteconsists of a Clearinghouse for Scientific and Technical Information,3 a Center forComputer Sciences and Technology, and a group of technical divisions and officesorganized by the following fields of technology:

Building Research—Electronic Instrumentation— Technical Analysis— ProductEvaluation—Invention and Innovation— Weights and Measures —* EngineeringStandards—Vehicle Systems Research.

THE CENTER FOR RADIATION RESEARCH engages in research, measurement,and application of radiation to the solution of Bureau mission problems and theproblems of other agencies and institutions. The Center for Radiation Research con-sists of the following divisions:

Reactor Radiation—-Linac Radiation—Applied Radiation—Nuclear Radiation.1 Headquarters and Laboratories at Gaithersburg, Maryland, unless otherwise noted ; mailing address Washington, D. C. 20234.2 Located at Boulder, Colorado 80302.3 Located at 5285 Port Royal Road, Springfield, Virginia 22161.

NATIONAL BUREAU OF STANDARDS REPORT

NBS PROJECT NBS REPORT

3120625 9909

(Test No. 196180)

IMPACT PROPERTIES OF ALUMINUM ALLOY - BETA

SILICON CARBIDE WHISKER COMPOSITES

By

I. J. Feinberg

Engineering Metallurgy Section

Metallurgy Division

To

Melpar, Inc.

(USAF Contract No. F336 1 5 -6 8- C - 1 0 6 4)

IMPORTANT NOTICE

NATIONAL BUREAU OF STAN

for use within the Government. Be

and review. For this reason, the pi

whole or in part, is not authorizer

Bureau of Standards, Washington, I

the Report has been specifically pre

Approved for public release by the

Director of the National Institute of

Standards and Technology (NIST)

on October 9, 2015

accounting documents intended

Djected to additional evaluation

iting of this Report, either in

iff ice of the Director, National

le Government agency for which

2s for its own use.

U.S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

j,

HR

!'

Impact Properties of Aluminum Alloy - BetaSilicon Carbide Whisker Composites

Hater i a 1 : Thirty-one subsize Charpy V-notch impact test specimenswere submitted by the Materials Laboratory, Melpar, Incorporatedfor tests. The test material included specimens machined fromextruded 2024, 6065, and 7075 aluminum alloy blanks and specimensmachined from extruded 2024, 6065, and 7075 aluminum alloy -

silicon carbide composites.

Test Specimens : Figure 1 shows the configuration of the subsizeimpact test specimen and contains pertinent dimensions.

Test Procedure and Equipment ; All specimens were conditioned atroom temperature (j0° F) for at least one-half hour before testingThey were broken in a Baldwin 2 foot pound capacity impact tester.This machine has a C-type pendulum. The striker is rounded to aradius of 0.125 inches and the points of specimen support are 1,78inches apart. Figure 2 is a view of the impact tester with a testspecimen in place for testing.

Test Resul ts : Table 1 gives the test results.

p -

Table 1„ Charpy Impact Properties of Aluminum AlloyBlanks and Aluminum Alloy - Beta Silicon

Carbide Whisker Composites

Mel par SpecimenI dent i f i ca t i on

EnergyAbsorbed Remarks

Foot Pounds

A 1 2024 Blanks, 1HTB 31Spec, i 0.250

2 .235

3 .256

4 .236

Avg. .244

A1 2024 Composites,Spec. 1

2

3

4

Avg.

VHTL 420.017.017

.019 Some cladding

.015

.017

Alloy 889 ( A 1 97 1/2$ - Si 2 1/2$) BlanksSpec. 1 0.572

2 .531

3 .5274 .606Avg. .559

Alloy 889 (A 1 97 1/2$ - Si 2Spec. I

2

3

Avg.

1/2$) Composites, VSSL ^30.0440.O38O 0.121 In. notch depth,

0.151 In. square.

.0320 0.115 In. notch depth,0.143 In. square

.

.0380

Alloy 889 ( A 1 97Spec. 1

OCL.

1 /2$

3

Avg.

Si 2 1/2$) Composites, VSSM 440.027.026

.031

.028

- 3 -

Table 1 . Cont i nued

Melpar Specimen EnergyI dent i f i cat i on Absorbed

Foot Pounds

A1 7075 Composites, VHT8 32Spec. A

B

C

D

Avg.

A1 6o6l Composites, VHTM 45Spec. 1

OC.

3

4

5

Avg.

0.250.190

.255

.238

.233

0.027.027

.030

.031

.033

.030

AI 7075 Composites, VHTL 4l

Spec . A 0.017B .016

c .005D .018

Avg. .014

Remarks

Rema r ks : With only one exception, specimen C, A1 7075 Composite,VHTlTT, test results showed little scatter. Shear lipsindicative of good ductility were observed on the fracturesurfaces of all of the aluminum alloy blank specimens. Thefracture surfaces of the composite specimens were generally flatindicating embrittlement.

USCOMM-NBS-DC

FIGURE

1.

SUBSIZE

IMPACT

SPECIMEN

MELPAR

TESTS

o

LU

i/I

Figure Baldwin Impact Tester - 2 foot pound capacity

\